diff options
| author | Mateusz Litwin <mateusz.litwin@nokia.com> | 2025-12-18 22:33:04 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2026-01-17 16:35:33 +0100 |
| commit | 69695f5331d4d670eff76376faa3aeb5d68733e3 (patch) | |
| tree | 39eae7c89873d0f658aaf6097c51ec1740bcc997 | |
| parent | 81531bdea972c3cd8f147f61ca6027fa24e08fc3 (diff) | |
spi: cadence-quadspi: Prevent lost complete() call during indirect read
[ Upstream commit d67396c9d697041b385d70ff2fd59cb07ae167e8 ]
A race condition exists between the read loop and IRQ `complete()` call.
An interrupt could call the complete() between the inner loop and
reinit_completion(), potentially losing the completion event and causing
an unnecessary timeout. Moving reinit_completion() before the loop
prevents this. A premature signal will only result in a spurious wakeup
and another wait cycle, which is preferable to waiting for a timeout.
Signed-off-by: Mateusz Litwin <mateusz.litwin@nokia.com>
Link: https://patch.msgid.link/20251218-cqspi_indirect_read_improve-v2-1-396079972f2a@nokia.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | drivers/spi/spi-cadence-quadspi.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/drivers/spi/spi-cadence-quadspi.c b/drivers/spi/spi-cadence-quadspi.c index 3231bdaf9bd0..1cca9d87fbde 100644 --- a/drivers/spi/spi-cadence-quadspi.c +++ b/drivers/spi/spi-cadence-quadspi.c @@ -769,6 +769,7 @@ static int cqspi_indirect_read_execute(struct cqspi_flash_pdata *f_pdata, readl(reg_base + CQSPI_REG_INDIRECTRD); /* Flush posted write. */ while (remaining > 0) { + ret = 0; if (use_irq && !wait_for_completion_timeout(&cqspi->transfer_complete, msecs_to_jiffies(CQSPI_READ_TIMEOUT_MS))) @@ -781,6 +782,14 @@ static int cqspi_indirect_read_execute(struct cqspi_flash_pdata *f_pdata, if (cqspi->slow_sram) writel(0x0, reg_base + CQSPI_REG_IRQMASK); + /* + * Prevent lost interrupt and race condition by reinitializing early. + * A spurious wakeup and another wait cycle can occur here, + * which is preferable to waiting until timeout if interrupt is lost. + */ + if (use_irq) + reinit_completion(&cqspi->transfer_complete); + bytes_to_read = cqspi_get_rd_sram_level(cqspi); if (ret && bytes_to_read == 0) { @@ -813,7 +822,6 @@ static int cqspi_indirect_read_execute(struct cqspi_flash_pdata *f_pdata, } if (use_irq && remaining > 0) { - reinit_completion(&cqspi->transfer_complete); if (cqspi->slow_sram) writel(CQSPI_REG_IRQ_WATERMARK, reg_base + CQSPI_REG_IRQMASK); } |